Twelve elephants were killed in Kenya's Tsavo East National Reserve last week, the country's worst such slaughter in close to 30 years.

Two poachers were shot dead on Thursday in Kenya's north after the country's wildlife service intercepted them carrying eight elephant tusks from freshly-killed elephants. Two other men were arrested in the same incident.

Rangers with sniffer dogs and teams in helicopters are continuing to hunt for the gang that killed the 12 elephants in Tsavo, but there were fears that they had already escaped.